This invention relates to jewelry settings of the prong type. More specifically, the invention relates to an arrangement for setting a gemstone in a prong type setting and to the finishing of the setting.
One popular method of setting gemstones in jewelry is to provide prongs which support the stone by means of notches in the prongs. The stone is supported at an outer periphery by the prongs, which has the advantage of displaying a large proportion of the gemstone. This arrangement is particularly popular for jewelry which displays precious or semiprecious stones, although the technique can be used for displaying rhinestones and non-precious decorative items.
In such setting of gems for jewelry, a set of prongs are provided. The gem setter uses a pliers to bend or twist the prongs of the setting into place to hold a gem. In inserting a stone into such a support, the support is typically expanded to accept the stone and then compressed over the stone. The pliers sometimes scratch the surface of the prong, requiring the prong to be re-polished. The amount of force needed to effect precisely the desired amount of plastic distortion of the prongs is often difficult to gauge, resulting in unstable settings.
A common occurrence is the gem setter pushing too hard on the pliers, or allowing the pliers to slip, in either case causing the gem to fracture.
One type of prior art setting is exemplified by the Tru-Seat setting, e.g., as described in U.S. Pat. No. 5,671,613. Such an arrangement is helpful for round gems but not as much for odd-shaped ones.
Alternatively in the prior art, the gem setter uses a pliers to twist the prongs of the setting into place to hold a gem. It is noted that the pliers would sometimes scratch the surface of the prong, requiring the prong to be re-polished.
U.S. Pat. No. 5,800,574, to Ricci, et al., a setting and a method of making a setting that includes a V-end prong member having two V-shaped prongs preferably fabricated from a single length of material such as, for example, a round wire. Two grooves are die-struck into the length of material and extend from a center portion of the length of material toward opposite ends thereof. The length of material is blanked so as to trim excess material therefrom, forming a blank having opposite, receptacle-defining end portions, and a central portion. The blank is then bent so that the receptacles face each other to define the V-end prong member having two V-shaped end prongs and a central portion. A conventional prong member can then be attached to the central portion of the V-end prong member. The prong member includes spaced distal ends that confine the article between the spaced distal ends and the receptacles.
U.S. Pat. No. 6,038,751, to Butler shows a jewelry setting for accommodating stones of various sizes, having two or more substantially straight prongs. Each prong is angularly directed from a common location in a base. To set the stone, the worker seats the stone at a height above the base without adjusting the angular direction of the prongs. The worker then shaves the distal ends of the prongs, such that the prongs do not extend substantially past the height of the seated gem. The shaving can be done by using a tool, such as a bearing cutter. In that arrangement, each prong is formed with an inwardly directed notch formed adjacent the distal ends of the prongs, this being accomplished after the prongs are shaved to an appropriate size. This patent does not suggest applying torque to the arms, and teaches shaving the arms before even the notches are formed. The setting entirely omits any horizontal element, such as a crossbar. This omission would make the setting less stable if one were to exert a torque on any of the prongs to twist them inwardly over the edge of a gemstone.
U.S. Pat. No. 4,750,245, to Moussoris describes an apparatus for mounting gemstones in prong-type settings by cutting a seat in the form of an inset edge in the ends of the prongs and swaging the remaining prong material over a stone girdle. A vertical support frame holds a tool driver such as a rotating chuck assembly slidably mounted thereon. A swaging element, which is removably coupled with the tool driver, contacts the ends of setting prongs after being cut. The swaging element bends a portion of the prong ends over the girdle of the stone. A micrometer is used to facilitate the swaging operation. The swage socket has a hemispherical opening which contacts the prongs of the setting. As the prongs engage the outer portion of the opening 148 they are slowly deflected inward toward the center of the stone, thus folding over the edge of the stone girdle. In this manner, the entire prong is bent.
In U.S. Pat. No. 5,855,048, to Synowicki, et al., a tool is used for mounting a solitaire gemstone in the head of a ring or earring. The tool holds a jewelry setting at the base.
In U.S. Pat. No. 5,800,574, to Ricci, et al., a setting includes a V-end prong member having two V-shaped prongs preferably fabricated from a single length of material such as, for example, a round wire. Two grooves are die-struck into the length of material and extend from a center portion of the length of material toward opposite ends thereof. The length of material is blanked so as to trim excess material therefrom, forming a blank having opposite, receptacle-defining end portions, and a central portion. The blank is then bent so that the receptacles face each other to define the V-end prong member having two V-shaped end prongs and a central portion. A conventional prong member can then be attached to the central portion of the V-end prong member. The prong member includes spaced distal ends that confine the article between the spaced distal ends and the receptacles. The gemstone is set using prongs formed of sheets of metal having a V-shaped cross section.
It is desired to provide a setting which can be assembled easily and with reduced incidence of gemstone breakage. In doing so, it is desired to control an amount of force applied to the setting so as to transfer a desired amount of force. The force should be sufficient to assure secure retention of the gemstone by the setting, but low enough to minimize breakage. It is desired to provide a method for applying precisely controlled amounts of force to prongs in a prong setting. In particular, since a prong setting is normally adjusted by bending at a base of the prongs or just above a lateral support for the prongs, it is desired to control an amount of torque applied to the prongs.
When using tools to apply torque to prongs, another form of damage which can occur is gouging or spalling of the prongs. Standard practice is to apply pressure with a pliers or a similar clamping tool which is intended to limit damage to the prongs, and if damage occurs, attempt to polish the damaged area sufficiently to remove the marks. The use of tools also tends to result in the prongs shifting in undesired directions. This distorts the shape of the setting, weakens the setting""s grip on the gemstone and weakens the prongs. Nevertheless, gemstones are commonly set manually, meaning without precision torque control apparatus. It is therefore desired to provide an ability to easily set a gemstone in a prong setting with sufficient force to secure the stone, without unduly stressing the stone. It is further desired to accomplish this in a manner which does not result in marring the final product. In addition, it is desired to provide a heavier or sturdier prong setting so that the stone is more securely mounted.
The present invention provides an improved method and apparatus for setting gems, e.g. for use in a gold or other precious metal ring or brooch. According to one aspect of the present invention, extended ends on a plurality of prongs perform a lever arm function, which facilitates bending the prongs. Bending of the prongs in accordance herewith results in the prongs securely engaging against the gemstone with reduced tendency to fracture the gemstone.
According to an optional aspect of the present invention, the prongs are reinforced to provide stability. In one configuration, a horizontal element, such as a crossbar is provided. The use of reinforcement enhances stability of the prongs. This is beneficial when a torque is exerted on any of the extended ends, for example to twist them inwardly over the edge of a gemstone.
In the present invention, prongs that hold the gem in the setting are cast or struck with a lever arm in the form of a flange extending therefrom. The flange provides a lever extension to the prong, and is used to manipulate the end of the prong. This integral lever extension provides a secure handle by which a force or torque can be applied without the risk of slipping and damaging the setting or gemstone.
To set a gem, the worker positions a gem into place. The worker then applies a clamping tool or wrench to an individual one of the levers, and the force performs a lever function to gently twist the end of the lever arm into place in a controlled manner. The prongs engage the gemstone at a girdle location on the gemstone, at which time the prongs deform at the notches. In one embodiment the tool may be controlled by hand feel. In another embodiment the tool may include a torque-measuring or torque-limiting device to control the pressure applied to the stone by the prong, thus minimizing likelihood of breaking the gem. The worker then applies the tool successively to other levers as needed to gently move the prongs in a controlled manner into place until the gem is securely mounted. The levers are then removed from each prong by cutting and/or grinding them away, and the surface of each prong is then polished.
The invention provides an improved technique for setting gems. A gem setting includes at least one prong. The prong(s) have an indent positioned at an upper distal end functioning to hold a edge of a gem or xe2x80x9cgirdle.xe2x80x9d In one particular configuration, the prong(s) have a V-shaped indent. A lever extension extends upwardly from each of the prongs.
In an optional aspect of the invention, a cross member positioned at lower end securely connects the prongs.
After the gemstone is set, the extended ends of the prongs are cut off to leave exposed ends, and the exposed ends are polished.
An advantage of the present invention is that a significantly heavier prong may be used, thereby providing a tighter and more durable setting. In particular, the notched portion of the prong at the girdle can be made significantly heavier. Therefore a heavier prong profile to be used, resulting in a tighter and more durable setting.
According to one aspect of the present invention, a gemstone setting can be assembled easily and with reduced incidence of gemstone breakage. In setting the gemstone, a controlled amount of force is applied to the setting so as to transfer a desired amount of force. The force is sufficient to assure secure retention of the gemstone by the setting, but low enough to minimize breakage. Precisely controlled amounts of force are applied to prongs in a prong setting. In particular, a controlled amount of torque is applied to the prongs of a prong setting, thereby allowing adjustment by bending the prongs at a base of the prongs or just above a lateral support for the prongs, as well as bending the prongs over the gemstone.
The invention permits application of pressure using hand feel. This is done with a clamping tool, and results in a very controlled application of force. The invention permits the use of tools with a reduced tendency of causing the prongs to shift in undesired directions. This avoids distorting the shape of the setting, and assures that the setting has a strong grip on the gemstone without weakening the prongs. The invention provides an ability to easily set a gemstone in a prong setting with sufficient force to secure the stone, without unduly stressing the stone. This is achieved in a manner which does not result in marring the final product. The invention also facilitates providing a heavier or sturdier prong setting so that the stone is more securely mounted.